Nudge-Based Exercise Intervention for Adolescents With Obesity

This study will evaluate whether a nudge-based exercise program can improve body mass index (BMI) and physical activity in adolescents with obesity. About 140 adolescents aged 10-19 years will participate. Participants will be placed into one of two groups according to the order in which they are admitted to the hospital. One group will receive a standard exercise intervention, while the other group will receive an 8-week nudge-based exercise program designed to make regular physical activity easier to start and maintain. The nudge-based program uses simple behavioral strategies to make exercise easier to start and maintain, including framed and visual information, default exercise options, reminders, peer comparison and support, goal commitment, progress feedback, and small incentives. The program combines face-to-face sessions during hospitalization with home-based support, exercise tools, activity recording, and online follow-up. The main outcomes are changes in BMI and physical activity. Other outcomes include body composition, blood metabolic markers, health-related quality of life, and exercise self-efficacy. Assessments will be conducted before and after the intervention, with follow-up assessments used to examine whether the effects are maintained over time.